Add option to sort apps by first letter in the scrollbar

[Gamer750]

Checklist

• [X] I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• [X] I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• [X] I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• [X] I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• [X] This issue contains only one feature request.
• [X] I have read and understood the contribution guidelines.
• [X] I optionally donated to support the Fossify mission.

Feature description

Like this

https://github.com/FossifyOrg/Launcher/assets/141329708/dd08bcf9-a0b5-41f2-85d1-d3da80f3e99b

Why do you want this feature?

The app will become more user friendly

Additional information

No response